Aplikace prostorových konečných prvků pro řešení interakce základů s podložím

Abstract

Application of 3D finite elements for solving of subsoil-structure interaction is the main focus of the doctoral thesis. Analytical equations for solving of subsoil-structure interaction, in the past derived by various Czech and foreign authors, were solved only for simple shapes of foundation and load. Therefore, the analytical solutions are often replaced by numerical solutions. A set of experimental loading tests of steel-fibre reinforced concrete was realized in 2016 using the unique experimental equipment. A set of experimental loading tests contain of the same dimensions four concrete slabs on the same subsoil. Slabs differed mainly in the amount of wires added to concrete. Numerical analysis based on the finite element method (FEM) was performed for the entire set of experimental loading tests. Within the doctoral thesis were created 3D numerical models of slabs using finite element which enabled non-linear analysis of concrete structures, the formation of plastic deformation or taking into account the influence of the reinforcement and the influence of crack. The numerical model of the subsoil was also created by the 3D finite elements. In the 3D numerical models in which the subsoil was modelled as a linear elastic homogeneous isotropic continuum, the results are greatly dependent on the chosen parameters entering into the calculation. These parameters are eg. the size of the modelled area representing the subsoil, the choice of boundary conditions or the mesh size. This can be partly solved by using inhomogeneous elastic half-space in which the concentration of stress in the vertical axis of the foundation is different from the concentration in the homogeneous half-space. The modulus of deformation increases with increasing depth in inhomogeneous elastic half-space. Within the doctoral thesis the subsoil-structure interaction was solved by analyses of numerical model, in which was applied analytical solutions of inhomogeneous half-space (Ohde, 1939) found during background research world scientific literature.